1. Field of the Invention
The present invention relates to an image detecting system and method for extracting video signal parameters from uncompressed digital video data.
2. Description of the Related Art
In order to improve transmission efficiency, images containing a huge amount of data are typically compressed then transmitted over a transmission medium to a decoder, which is operative to decode the coded video data. A common coding method used is based on the discrete cosine transform (DCT). The DCT method has been adapted to international standard coding methods, such as JPEG (Joint Photographic Expert Group) and MPEG (Moving Picture Expert Group).
In digital video processing chains, uncompressed (or decoded) digital video data undergoes further down-stream processing, such as artifact reduction, quality enhancement, re-encoding, and editing. However, much care must be taken to identify and process the previously compressed digital video. For example, new displays such as LCOS and LCD have lower thresholds for artifact visibility; thus, the video enhancement algorithms must be tuned carefully to avoid enhancing artifacts. Accordingly, a reliable detector is needed to extract certain compression parameters from the decoded video data, such that the extracted quantization parameters can be adjusted to improve the displayed video quality by coding the local parts of video, or by re-encoding or transcoding of the previously compressed video data.